Biocompatibility Studies on Bone Marrow Stromal Cells with Chitosan-gelatin Blends

1　IntroductionSuccessfulmanagementofcartilagedefectsremainsamajorclinicalchallengetoorthopedicsurgeons .Theneedformoreeffectivemethodsofrepairingcartilagedefectshaspromptedinvestigationintotheutilityoftissueengi neeringapproachesrecently .Thechoiceofbiom…     

Periodontal ligament cells cultured on the tricalcium phosphate/chitosan scaffolds in vivo and in vitro

To search suitable scaffolds for periodontal tissue regeneration, different ratios of tricalcium phosphate/chitosan(TCP/chitosan) scaffolds were prepared through a freeze-drying process. Human periodontal ligament cells(HPLCs) were incubated on the scaffolds in vitro. Cells were cultured on the scaffolds, detected by scanning electron microscopy (SEM). HPLCs were analyzed by MTT assay and alkaline phosphatase(ALP) activity detection. HPLCs were seeded onto the scaffolds. Then these scaffolds with HPLCs were implanted subcutaneously into athymic mice. The state of periodontal tissue regeneration was detected after 4 weeks. As the ratio of TCP increased, TCP/chitosan scaffolds accelerated HPLCs proliferation significantly higher than the pure chitosan scaffold. HPLCs produced the cementoid tissue in vivo. The periodontal tissue regeneration engineering is able to be applied with TCP/chitosan scaffolds.     

A biomimetic bi-layered tissue engineering scaffolds for osteochondral defects repair

Osteochondral defects are most commonly characterized by damages to both cartilage and underlying subchondral bone tissues,thus developing bi-layered scaffold that can concurrently regenerate these two specific lineages becomes challenge. In this study,the highly biomimetic bi-layered scaffolds were successfully prepared using human-like-collagen(HLC), hyaluronan(HA) and nano hydroxyapatite(HAP) particles, combined with "liquid phase synthesis" technology, freeze-drying and chemical crosslinking techniques, which was simulated the composition of natural extracellular matrix to repair osteochondral defects. This novel bilayer osteochondral graft had a seamlessly integrated layer structure, suitable pore size, high levels of porosity, and excellent mechanical properties. In vitro cell experiments of the bilayer scaffold indicated that the scaffold could promote the proliferation and adhesion of human bone marrow mesenchymal stem cells. In vivo osteochondral defects and micro-CT experiment revealed that bilayer scaffolds showed complete closure of the defect. Histology confirmed collagen and glycosaminoglycans were deposited in the new matrix of hyaline cartilage and bone in the bilayer scaffold group. Therefore, the developed bionic bilayer scaffold enhanced the regeneration of hyaline cartilage through subchondral bone formation and lateral host-tissue integration. In conclusion, this bilayer scaffold based on HLC could be used as the desired strategy for osteochondral defects regeneration.     

Preliminary biocompatibility evaluation of regenerated <Emphasis Type="Italic">Antheraea yamamai</Emphasis> Silk Fibroin <Emphasis Type="Italic">in vitro</Emphasis>

The study aimed to investigate the adhesion, morphology and proliferation of Sprague Dawley (SD) albino rat bone marrow-derived mesenchymal stem cells (BMSCs) by inverted microscope, cell counting, MTT test and laser scanning confocal microscop (LSCM). On the regenerated A yamamai SF film or blend films, the cell morphology was almost the same as that on collagen (collagen type I) film, the cell adhesion rate was higher than that on plastic cell plate and B mori SF film after 1 h (p < 0.01) of culture, and the cell proliferation was significantly higher than that on collagen film (p < 0.01) and plastic cell plate (p < 0.01), and also obviously better than that on B mori SF film. On the other hand, the viability of BMSCs in the regenerated A yamamai SF porous scaffold was better than that in B mori SF porous scaffold and medical grade polyvinyl alcohol (PVA) sponge.     

TGF-beta 1 Gene-Activated Matrices Regulated the Osteogenic Differentiation of BMSCs

Poly （lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol）（PLGA-[ASP-PEG]） scaffold materials were linked with a novel nonviral vector （K）16GRGDSPC through cross linker Sulfo- LC-SPDP to construct a new type of nonviral gene transfer system. Eukaryotic expressing vector containing transforming growth factor beta 1 （pcDNA3-TGFβ1） was encapsulated by the system. Bone marrow stromal cells （BMSCs） obtained from rabbit were cultured on PLGA-[ASP-PEG] modified by （K）16GRGDSPC and TGF-β1 gene and PLGA-[ASP-PEG] modified by （K）16GRGDSPC and empty vector pcDNA3 as control. The expressions of osteogenic makers of the BMSCs cultured on the TGF-β1 gene-activated scaffold materials were found significantly higher than those of the control group （P〈0.05）. A brand-new way was provided for regulating seed cells to directionally differentiate into osteoblasts for bone defect restoration in bone tissue engineering.     

Chondrogenesis of Precartilaginous Stem Cells in KLD-12 Self-assembling Peptide Nanofiber Scaffold Loading TGF-β3 Gene

The effect of culture in KLD-12 self-assembling peptide nanofiber scaffold containing TGF-β3 gene on differentiation of precartilaginous stem cells (PSCs) into chondrocytes was studied. KLD-12 was synthesized by solid-state method. After TGF-β3 plasmid was loaded into KLD-12 self-assembling peptide nanofiber scaffold, DNA release ability was investigated. PSCs and hTGF-β3 gene were loaded into KLD-12 3-D scaffold, and MTT assay was performed to investigate the cell proliferation, and ELASA assay was used to...     

HBsAg壳聚糖疫苗制备工艺及相关研究

研制以壳聚糖为载体的乙型肝炎疫苗,将乙肝病毒表面抗原疫苗包封在壳聚糖微球中,制备鼻腔免疫的新型微球疫苗,通过鼻腔注入免疫小鼠．普通乙肝疫苗由腹腔注入免疫小鼠．用ELISA方法检测血清中抗HBV的IgG,结果显示鼻腔及腹腔免疫效果无显著性差异．HBsAg壳聚糖微球疫苗的制备为鼻腔免疫乙型肝炎疫苗的开发提供了实验基础．     

Repair of Rat Segmental Defects with Mineralized Collagen Grafts Combined with or without Mesenchymal Stem Cells and BMP-2

1Introduction Thepreferredtreatmentofbonedefectsisautologousbonegraft.However,itslimitedsupplyandassociatedmorbiditylimititsuse.Immunologicalreactionsandriskofcontaminationlimittheuseofallograftbone.Bonegraftsubstitutesaretheremainingoption.Wehavedevelope…     

In vitro characterization of PBLG-g-HA/ PLLA nanocomposite scaffolds

The purpose of the present study was to synthesize a new composites scaffold containing poly(γ-benzyl-L-glutamate) modified hydroxyapatite/(poly(L-lactic acid))(PBLG-g-HA/PLLA) and to investigate their in vitro behaviour on bone mesenchymal stromal cells(BMSCs). The results demonstrated that BMSC proliferation was signifi cantly increased on PBLG-g-HA/PLLA scaffolds after 3 and 7 days post seeding when compared to PLLA and HA/PLLA scaffolds. The in vitro osteogenic differentiation also favoured the composite PBLG-g-HA/PLLA scaffolds when compared to controls by signifi cantly increasing Runx2, ALP or osteocalcin mRNA expression as assessed by real-time PCR. The results illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications. And the in vivo testing further confi rms the PBLG-gHA/PLLA scaffolds' potentioal for healing critical bone defects.     

Chitosan—L- lactic acid scaffold for the regeneration of peripheral nerve and its NGF release properties

Chitosan—L-lactic acid composite scaffold for the regeneration of peripheral nerve is obtained by grafting L-lactic acid onto the amino groups in chitosan with combined vacuum freezer drier. The composite scaffold was characterized by ATR-FTIR and SEM. The scaffold has a better graft efficiency and has a dense inner layer and a loose outer layer with porous structure, and the pore size is about 100 μm. The NGF release properties of the scaffold were investigated. The experimental results showed that, at the 1st day, 15.2 ng of NGF on average was released from the scaffold. From day 2 to day 10, the release rate obviously slowed down and 1.64 ng of NGF was released on average every day. After 10 days, the release rate was slower and 10.3 ng of NGF was released on average every day. After 60 days, NGF could also maintained a certain concentration. These properties show that the scaffold is a better carrier for NGF which can be more advantageous to the regeneration of the damaged peripheral nerve. As a result, this composite scaffold would be an ideal candidate for the regeneration of damaged peripheral nerve.     

基于离散单元法的人工骨材料微观结构研究

人工骨支架的孔隙率是影响体液在人工骨内部循环和细胞在内部生长能力的重要参数.利用离散单元法分析人工骨支架制备过程中羟基磷灰石微球的堆积过程,根据每一时刻各颗粒间的相互作用计算接触力,再运用牛顿第二定律计算单元的运动参数,从而实现对运动情况的预测.在颗粒的碰撞过程中,运动的颗粒必然趋于稳定,最终计算出稳定状态下人工骨支架的孔隙率和配位数.利用掺杂可溶解生物微球的方法调节人工骨支架的孔隙率和配位数,对人工骨支架孔隙率进行控制,实现了按照个体差异制备人工骨支架.对比前人晶格理论计算人工骨孔隙率的方法,验证了晶格理论的可行性,同时也体现了离散单元法的准确性.     

透明质酸钠/魔芋葡甘聚糖软骨支架材料的研究

采用共混法制备了透明质酸钠（SH）/魔芋葡甘聚糖（KGM）软骨支架材料,通过正交实验,根据抗压强度、吸水率、孔径分布和空隙率等对支架进行了制备条件（SH、KGM、氨水含量和冷冻温度）的优选,通过光学显微观察、XRD、IR、体外模拟降解、兔骨髓间充质干细胞共培养和SEM观察,初步检测了软骨支架的材料结构和生物性能,证明材料有较好的干细胞相容性,无短期急性毒性,可以进一步进行开发研究.     

壳聚糖为基质的左氧氟沙星缓释微球制备

以壳聚糖为基质,对左氧氟沙星缓释微球的制备方法进行了探索.确定了左氧氟沙星-壳聚糖缓释微球的制备工艺条件.通过考察微球的载药量及累积释放度,对上述制备方法工艺中的壳聚糖与盐酸左氧氟沙星的质量比、乳化剂Span用量、溶剂与壳聚糖溶液的体积比、交联剂戊二醛用量等因素进行了优化,制备出了具较好缓释效果的盐酸左氧氟沙星-壳聚糖缓释微球.该方法制备的左氧氟沙星-壳聚糖缓释微球载药量为43.88%,体外累积释放度的线形关系良好.     

The enhancement of osteogenesis by scaffold based on mineralized recombinant human-like collagen loading with rhBMP-2

A biomimetic scaffold based on mineralized recombinant collagen, nano-hydroxyapatite/recombinant human-like collagen/poly(lactic acid) (nHA/RHLC/PLA), was prepared with recombinant human bone morphogenic protein-2 (rhBMP-2) for improving the osteoinductive property of the scaffold. The nHA/RHLC/PLA scaffolds loaded with 10 μg rhBMP-2 and the unloaded scaffolds were implanted subcutaneously in the rat model. The osteogenetic capacity of these composites was evaluated by CT scan, ALP activity test and histological observation at 4 and 8 weeks after implantation. The experimental results indicated that the osteogenic capability of the scaffolds loaded with rhBMP-2 was superior to the unloaded scaffold. It was concluded that rhBMP-2 can enhance the osteoinductive property of the nHA/RHLC/PLA scaffold and the nHA/RHLC/PLA scaffold loaded with rhBMP-2 have the good potential of being used in bone tissue engineering.     

In vitro and in vivo characterization of homogeneous chitosan-based composite scaffolds

With a homogeneous distribution of hydroxyapatite (HAP) crystals in polymer matrix, composite scaffolds chitosan/ HAP and chitosan/collagen/HAP were fabricated in the study. XRD, SEM and EDX were used to characterize their components and structure, in vitro cell culture and in vivo animal tests were used to evaluate their biocompatibility. HAP crystals with rod-like shape embeded in chitosan scaffold, while HAP fine-granules bond with collagen/chitosan scaffold compactly. A homogenous distribution of Ca and P elements both in chitosan/HAP scaffold and chitosan/collagen/HAP scaffold was defined by EDX pattern. The presence of collagen brought a more homogenous distribution of HAP due to its higher ability to induce HAP precipitation. The results of in vitro cell culture showed that the composite’s biocompatibility was enhanced by the homogenous distribution of HAP. In vivo animal studies showed that the in vivo biodegradation was effectively improved by the addition of HAP and collagen, and was less influenced by the homogeneous distribution of HAP when compared with a concentrated distribution one. The composite scaffolds with a homogeneous HAP distribution would be excellent alternative scaffolds for bone tissue engineering.     

The Bisphosphonate Clodronate Modifying Hydroxyapatite Bioceramics for Bone Scaffold

To investigate the efficiency of clodronate modifying HA bioceramics,and to evaluate the effect of clodronate modifying HA bioceramics on the cells in vitro,clodronate modified the porous HA bioceramics for bone scaffold by chelation .The outermost layer of the specimens was analyzd by XPS and FI-IR ,The depth profile was investigated by the argon-ion sputtering method.The cell culture test was conducted using MC3T3-E1 osteoblastic cells,The cells were inoculated and cultured on the scaffolds.Morphological observation of the cells,MTT test and ALP activity test evaluated the cell attachment ,proliferation and activity on the scaffolds.The cell culture test in cell quantity and morphology indicated active proliferation of the cells on the scaffolds.The ALP activity of the cells cultured for 3d and 7d on clodronate-HA bioceramics was slightly higher than that on HA bioceramics ,but the difference was not signifcant,This result indicated that clodronate-HA bioeramics had favorable cytocompatibility to be used as bone scaffold with potential ability to improve asteogensis.     

A Novel Guided Bone Regeneration Membrane Composed of Nano-hydroxyapatite and Aliphatic Polyester-amide

1Introduction Guidedboneregeneration(GBR)methodisawell establishedtherapytotreatbonedefects.Theprincipleof GBRmethodistopreventaninvasionofsofttissuecells frominterferingwithosteogenesis.GBRmembranesalso haveanimportantfunctionwhichencouragesbone growth.T…     

The Bisphosphonate Clodronate Modifying Hydroxyapatite Bioceramics for Bone Scaffold

1Introduction Variousbiomaterialsareincreasinglyusedasbone substitutesinorthopedicsurgery,oralandmaxillo facial surgery.Toserveasabonesubstitute,thematerialmust bebiocompatible,osteoconductive,andosteointegrative.Hydroxyapatite(HA)hasfavorablebiocompatibi…     

掺锶聚磷酸钙的微观结构、体外降解性能和血管内皮细胞相容性研究

以聚磷酸钙（CPP）为对照,研究掺锶聚磷酸钙（SCPP）微观结构、体外降解产物和速率以及血管内皮细胞相容性,探讨了掺锶对CPP结构性能的影响。结果表明,掺锶改变材料的微观结构与降解性能。与CPP相比,SCPP材料晶粒变大,晶粒间连接更紧密形成平整表面;14 d SCPP降解释放的Ca2+和Pi浓度显著下降,即降解速率变慢,降解产物中出现Sr2＋,且浓度随时间增加。体外细胞培养结果显示,掺锶能提高材料与血管内皮细胞的相容性。SCPP表面内皮细胞更易粘附、铺展,融合生长形成单层内皮覆盖材料表面。SCPP降解液能显著促进内皮细胞的增殖(p<0.05),经多元逐步回归分析知,降解液中的Sr2＋为影响增殖的主要因素(R2=0.670, p<0.01)。SCPP较CPP具有更好的血管内皮细胞相容性,可能促进血管的形成,是更理想的骨组织工程支架材料。     

人脐带与骨髓来源间充质干细胞miRNA的差异表达

采用基因芯片技术检测了人脐带与骨髓两种不同来源间充质干细胞中miRNA的表达.结果表明:有26个miRNA差异表达,其中miR-29b、miR-20a、miR-31、miR-20b及miR-106a在人脐带间充质干细胞(UMSCs)中表达显著上调,差异倍数均高于3,miR-138则表达下调.在此基础上,采用实时荧光定量PCR技术对差异性显著的6个miRNA进行验证,检测结果一致.最后对特异性基因进行靶点预测,发现靶基因与mRNA转录、翻译以及细胞增殖、分裂、信号转导等功能相关.